The principal objective of this Program is to gain a more complete understanding of the mechanisms of myocardial contraction and its regulation. Supporting this objective are similar studies of the regulation of coronary flow involving studies at the cellular level of coronary smooth muscle function and the thermal and chemical kinetics of skeletal muscle. The basic disciplines of muscle mechanics and electrophysiology, membrane ionic exchange, ion adsorption on fixed charge matrices, and myofilament chemical and thermal kinetics are all combined by specialty groups of international prominence to pursue these studies.